Health-Damaging Climate Events Highlight the Need for Interdisciplinary, Engaged Research

In 2023 human populations experienced multiple record-breaking climate events, with widespread impacts on human health and well-being. These events include extreme heat domes, drought, severe storms, flooding, and wildfires. Due to inherent lags in the climate system, we can expect such extremes to continue for multiple decades after reaching net zero carbon emissions. Unfortunately, despite these significant current and future impacts, funding for research in climate and health has lagged behind that for other geoscience and biomedical research. While some initial efforts from funding agencies are evident, there is still a significant need to increase the resources available for multidisciplinary research in the face of this issue. As a group of experts at this important intersection, we call for a more concerted effort to encourage interdisciplinary and policy-relevant investigations into the detrimental health effects of continued climate change.

Dust Storms, Valley Fever, and Public Awareness

We discuss several issues raised by Comrie (2021, https://doi.org/10.1029/2021GH000504), which uses a crowdsourced data set to study dust storms and coccidioidomycosis (Valley fever). There is inconsistency in the term "dust storm" used by science communities. The dust data from National Oceanic and Atmospheric Administration Storm Events Database are from diverse sources, unsuitable for assessing dust-coccidioidomycosis relationships. Population exposure to dust or Coccidioides needs to consider the frequency, magnitude, and duration of dust events. Given abundant evidence that dust storms are a viable driver to transport pathogens, it is in best public interest to advocate dust storms may put people at risk for contracting Valley fever.

[Takaki Kanehiro and the diet experiments of beriberi in navy in modern Japan]

Beriberi is a disease caused by insufficiency vitamin B₁ in the body which, if untreated, can cause death. It was the disease with the highest incidence in the Japanese army during the Meiji and Taisho Periods. It was treated with a variety of therapeutic treatments by the Navy and the Army respectively, based on the different therapy systems of Britain and Germany at the time, with an argument about these treatments lasting more than half a century. Eventually, the Navy experimented with dietary modification for beriberi, according to Takagi Kanehiro, successfully reducing beriberi incidence to zero. This rewrote the epidemic history of beriberi in the Japanese Navy.

Impacts of post-harvest open biomass burning and burning ban policy on severe haze in the Northeastern China

Open filed biomass burning is a major contributor to airborne particulate matter and reactive trace gases during the post-harvest season in the Northeastern China. Due to prevailing weather conditions and high emission density, this region is prone to the accumulation of air pollutants that often leads to severe haze events. In this study, we combined satellite and ground observations, and a regional air quality modeling system to quantify the contribution of open biomass burning to surface PM_2.5 (particulate matter with diameter less than 2.5 µm) concentrations during a severe haze episode. During this period (November 1^st - 4^th, 2015), the average PM_2.5 concentrations in Heilongjiang, Jilin, and Liaoning provinces reached 116.98 μg/m³, 98.60 μg/m³, and 70.17 μg/m³ respectively. Model simulations showed that open biomass burning contributed to 52.7% of PM_2.5 concentrations over Northeast China. Using the differences in active fire spots as detected by the Visible Infrared Imaging Radiometer Suites (VIIRS) aboard the Suomi-NPP, we estimated that the burning ban enforced in 2018 have caused the PM_2.5 concentrations to decrease from the 2015 level by 67.10%, 53.23%, and 10.06% in the Heilongjiang, Jilin, and Liaoning provinces respectively. Over the region, the burning ban proved to be effective in reducing fire emissions and lowering region-wide PM_2.5 concentration by 48.1% during the post-harvest season.

Intensified dust storm activity and Valley fever infection in the southwestern United States

Climate models have consistently projected a drying trend in the southwestern United States, aiding speculation of increasing dust storms in this region. Long-term climatology is essential to documenting the dust trend and its response to climate variability. We have reconstructed long-term dust climatology in the western United States, based on a comprehensive dust identification method and continuous aerosol observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. We report here direct evidence of rapid intensification of dust storm activity over American deserts in the past decades (1988-2011), in contrast to reported decreasing trends in Asia and Africa. The frequency of windblown dust storms has increased 240% from 1990s to 2000s. This dust trend is associated with large-scale variations of sea surface temperature in the Pacific Ocean, with the strongest correlation with the Pacific Decadal Oscillation. We further investigate the relationship between dust and Valley fever, a fast-rising infectious disease caused by inhaling soil-dwelling fungus (Coccidioides immitis and C. posadasii) in the southwestern United States. The frequency of dust storms is found to be correlated with Valley fever incidences, with a coefficient (r) comparable to or stronger than that with other factors believed to control the disease in two endemic centers (Maricopa and Pima County, Arizona).

Typical atmospheric haze during crop harvest season in northeastern China: A case in the Changchun region

This study presents the mass concentrations of PM_2.5, O₃, SO₂ and NO_x at one urban, one suburban and two rural locations in the Changchun region from September 25 to October 27 2013. Major chemical components of PM_2.5 at the four sites were daily sampled and analyzed. Most of daily concentrations of SO₂ (7-82μg/m³), O₃ (27-171μg/m³) and NO_x (14-213μg/m³) were below the limits of the National Ambient Air Quality Standard (NAAQS) in China. However, PM_2.5 concentrations (143-168μg/m³) were 2-fold higher than NAAQS_. Higher PM_2.5 concentrations (~150μg/m³) were measured during the pre-harvest and harvest at the urban site, while PM_2.5 concentrations significantly increased from 250 to 400μgm^-3 at suburban and rural sites with widespread biomass burning. At all sites, PM_2.5 components were dominated by organic carbon (OC) and followed by soluble component sulfate (SO₄^2-), ammonium (NH₄⁺) and nitrate (NO₃^-). Compared with rural sites, urban site had a higher mineral contribution and lower potassium (K⁺ and K) contribution to PM_2.5. Severe atmospheric haze events that occurred from October 21 to 23 were attributed to strong source emissions (e.g., biomass burning) and unfavorable air diffusion conditions. Furthermore, coal burning originating from winter heating supply beginning on October 18 increased the atmospheric pollutant emissions. For entire crop harvest period, the Positive Matrix Factorization (PMF) analysis indicated five important emission contributors in the Changchun region, as follows: secondary aerosol (39%), biomass burning (20%), supply heating (18%), soil/road dust (14%) and traffic (9%).

Does warmer China land attract more super typhoons?

Accurate prediction of where and when typhoons (or named hurricanes which form over the North Atlantic Ocean) will make landfall is critical to protecting human lives and properties. Although the traditional method of typhoon track prediction based on the steering flow theory has been proven to be an effective way in most situations, it slipped up in some cases. Our analysis of the long-term Chinese typhoon records reveals that typhoons, especially super typhoons (those with maximum sustained surface winds of greater than 51 ms(-1)), have a trend to make landfalls toward warmer land in China over the past 50 years (1960-2009). Numerical sensitivity experiments using an advanced atmospheric model further confirm this finding. Our finding suggests an alternative approach to predict the landfall tracks of the most devastating typhoons in the southeastern China.

An estimate of the global burden of anthropogenic ozone and fine particulate matter on premature human mortality using atmospheric modeling

BACKGROUND

Ground-level concentrations of ozone (O3) and fine particulate matter [< or = 2.5 microm in aerodynamic diameter (PM2.5)] have increased since preindustrial times in urban and rural regions and are associated with cardiovascular and respiratory mortality.

OBJECTIVES

We estimated the global burden of mortality due to O3 and PM2.5 from anthropogenic emissions using global atmospheric chemical transport model simulations of preindustrial and present-day (2000) concentrations to derive exposure estimates.

METHODS

Attributable mortalities were estimated using health impact functions based on long-term relative risk estimates for O3 and PM2.5 from the epidemiology literature. Using simulated concentrations rather than previous methods based on measurements allows the inclusion of rural areas where measurements are often unavailable and avoids making assumptions for background air pollution.

RESULTS

Anthropogenic O3 was associated with an estimated 0.7 +/- 0.3 million respiratory mortalities (6.3 +/- 3.0 million years of life lost) annually. Anthropogenic PM2.5 was associated with 3.5 +/- 0.9 million cardiopulmonary and 220,000 +/- 80,000 lung cancer mortalities (30 +/- 7.6 million years of life lost) annually. Mortality estimates were reduced approximately 30% when we assumed low-concentration thresholds of 33.3 ppb for O3 and 5.8 microg/m3 for PM2.5. These estimates were sensitive to concentration thresholds and concentration-mortality relationships, often by > 50%.

CONCLUSIONS

Anthropogenic O3 and PM2.5 contribute substantially to global premature mortality. PM2.5 mortality estimates are about 50% higher than previous measurement-based estimates based on common assumptions, mainly because of methodologic differences. Specifically, we included rural populations, suggesting higher estimates; however, the coarse resolution of the global atmospheric model may underestimate urban PM(2.5) exposures.

Using air quality modeling to study source-receptor relationships between nitrogen oxides emissions and ozone exposures over the United States

Human exposure to ambient ozone (O(3)) has been linked to a variety of adverse health effects. The ozone level at a location is contributed by local production, regional transport, and background ozone. This study combines detailed emission inventory, air quality modeling, and census data to investigate the source-receptor relationships between nitrogen oxides (NO(x)) emissions and population exposure to ambient O(3) in 48 states over the continental United States. By removing NO(x) emissions from each state one at a time, we calculate the change in O(3) exposures by examining the difference between the base and the sensitivity simulations. Based on the 49 simulations, we construct state-level and census region-level source-receptor matrices describing the relationships among these states/regions. We find that, for 43 receptor states, cumulative NO(x) emissions from upwind states contribute more to O(3) exposures than the state's own emissions. In-state emissions are responsible for less than 15% of O(3) exposures in 90% of U.S. states. A state's NO(x) emissions can influence 2 to 40 downwind states by at least a 0.1 ppbv change in population-averaged O(3) exposure. The results suggest that the U.S. generally needs a regional strategy to effectively reduce O(3) exposures. But the current regional emission control program in the U.S. is a cap-and-trade program that assumes the marginal damage of every ton of NO(x) is equal. In this study, the average O(3) exposures caused by one ton of NO(x) emissions ranges from -2.0 to 2.3 ppm-people-hours depending on the state. The actual damage caused by one ton of NO(x) emissions varies considerably over space.

Summertime state-level source-receptor relationships between nitrogen oxides emissions and surface ozone concentrations over the continental United States

Interstate transport of ozone (O3) and its precursors can contribute substantially to state-level surface o3 concentrations, making it difficult for some states to meet the National Ambient Air Quality Standards (NAAQS) for O3 by limiting only their own emissions. We analyze the effect of interstate transport on surface O3 in each continental U.S. state in July 1996 using the community multiscale air quality (CMAQ) model. By examining the difference between a baseline simulation and perturbation simulations in which each state's nitrogen oxides (NOx) emissions are removed, we establish for the first time a summertime source-receptor matrix for all 48 continental states. We find that for 16 (20) states at least one neighboring state's NOx emissions are responsible for a larger increase in monthly mean peak 8 h (all-hour) O3 concentrations than the state's own emissions. For over 80% of the contiguous states, interstate transport is more importantthan local emissions for summertime peak O3 concentrations. Our source-receptor matrices indicate that the geographic range of the clean air interstate rule (CAIR) was sufficient to address interstate transport of O3 in most of the states included in the program. However, the exclusion of Texas, which has particularly large NOx emissions, from the CAIR O3 program left emission sources uncontrolled that contribute more than 1 ppbv to the July mean of peak 8 h O3 concentrations in over a dozen states.

Characterization of major chemical components of fine particulate matter in North Carolina

This paper presents measurements of daily sampling of fine particulate matter (PM2.5) and its major chemical components at three urban and one rural locations in North Carolina during 2002. At both urban and rural sites, the major insoluble component of PM2.5 is organic matter, and the major soluble components are sulfate (SO4(2-)), ammonium (NH4(+)), and nitrate (NO3(-)). NH4(+) is neutralized mainly by SO4(2-) rather than by NO3(-), except in winter when SO4(2-) concentration is relatively low, whereas NO3(-) concentration is high. The equivalent ratio of NH4(+) to the sum of SO4(2-) and NO3(-) is < 1, suggesting that SO4(2-) and NO3(-) are not completely neutralized by NH4(+). At both rural and urban sites, SO4(2-) concentration displays a maximum in summer and a minimum in winter, whereas NO3(-) displays an opposite seasonal trend. Mass ratio of NO3(-) to SO4(2-) is consistently < 1 at all sites, suggesting that stationary source emissions may play an important role in PM2.5 formation in those areas. Organic carbon and elemental carbon are well correlated at three urban sites although they are poorly correlated at the agriculture site. Other than the daily samples, hourly samples were measured at one urban site. PM2.5 mass concentrations display a peak in early morning, and a second peak in late afternoon. Back trajectory analysis shows that air masses with lower PM2.5 mass content mainly originate from the marine environment or from a continental environment but with a strong subsidence from the upper troposphere. Air masses with high PM2.5 mass concentrations are largely from continental sources. Our study of fine particulate matter and its chemical composition in North Carolina provides crucial information that may be used to determine the efficacy of the new National Ambient Air Quality Standard (NAAQS) for PM fine. Moreover, the gas-to-particle conversion processes provide improved prediction of long-range transport of pollutants and air quality.

Integrated assessment of the spatial variability of ozone impacts from emissions of nitrogen oxides

This paper examines the ozone (O3) damages caused by nitrogen oxides (NO(x)) emissions in different locations around the Atlanta metropolitan area during a summer month. We calculate O3 impacts using a new integrated assessment model that links pollution emissions to their chemical transformation, transport, population exposures, and effects on human health. We find that increased NO(x) emissions in rural areas around Atlanta increase human exposure to ambient O3 twice as much as suburban emissions. However, increased NO(x) emissions in central city Atlanta actually reduce O3 exposures. For downtown emissions, the reduction in human exposures to O3 from titration by NO in the central city outweighs the effects from increased downwind O3. The results indicate that the marginal damage from NO(x) emissions varies greatly across a metropolitan area. The results raise concerns if cap and trade regulations cause emissions to migrate toward higher marginal damage locations.