Exhaust ventilation in attached garages improves residential indoor air quality

Previous research has shown that indoor benzene levels in homes with attached garages are higher than homes without attached garages. Exhaust ventilation in attached garages is one possible intervention to reduce these concentrations. To evaluate the effectiveness of this intervention, a randomized crossover study was conducted in 33 Ottawa homes in winter 2014. VOCs including benzene, toluene, ethylbenzene, and xylenes, nitrogen dioxide, carbon monoxide, and air exchange rates were measured over four 48-hour periods when a garage exhaust fan was turned on or off. A blower door test conducted in each garage was used to determine the required exhaust fan flow rate to provide a depressurization of 5 Pa in each garage relative to the home. When corrected for ambient concentrations, the fan decreased geometric mean indoor benzene concentrations from 1.04 to 0.40 μg/m³ , or by 62% (P<.05). The garage exhaust fan also significantly reduced outdoor-corrected geometric mean indoor concentrations of other pollutants, including toluene (53%), ethylbenzene (47%), m,p-xylene (45%), o-xylene (43%), and carbon monoxide (23%) (P<.05) while having no impact on the home air exchange rate. This study provides evidence that mechanical exhaust ventilation in attached garages can reduce indoor concentrations of pollutants originating from within attached garages.

Can changing the timing of outdoor air intake reduce indoor concentrations of traffic-related pollutants in schools?

Traffic emissions have been associated with a wide range of adverse health effects. Many schools are situated close to major roads, and as children spend much of their day in school, methods to reduce traffic-related air pollutant concentrations in the school environment are warranted. One promising method to reduce pollutant concentrations in schools is to alter the timing of the ventilation so that high ventilation time periods do not correspond to rush hour traffic. Health Canada, in collaboration with the Ottawa-Carleton District School Board, tested the effect of this action by collecting traffic-related air pollution data from four schools in Ottawa, Canada, during October and November 2013. A baseline and intervention period was assessed in each school. There were statistically significant (P < 0.05) reductions in concentrations of most of the pollutants measured at the two late-start (9 AM start) schools, after adjusting for outdoor concentrations and the absolute indoor-outdoor temperature difference. The intervention at the early-start (8 AM start) schools did not have significant reductions in pollutant concentrations. Based on these findings, changing the timing of the ventilation may be a cost-effective mechanism of reducing traffic-related pollutants in late-start schools located near major roads.

Colonization and infection due to multi-resistant bacteria in neonates: a single center analysis

BACKGROUND

In the last years the prevalence of multi-resistant pathogens (MRPs) has increased. Systemic infections remain important for neonatal morbidity and mortality.

PATIENTS

Neonates born between January 2011 and December 2012 and admitted to the neonatology before their tenth day of life were included into this retrospective analysis. Vancomycin-resistant Enterococci, Methicillin-resistant Staphylococcus aureus, Gram-negative bacilli with Extend Spectrum Beta Lactamase or AMP-C resistance were defined as multi-resistant pathogens (MRPs). MRP positive and negative patients were analyzed regarding clinical risk factors and the incidence of systemic infections.

RESULTS

635 neonates were admitted during the analysis period. In 31 patients MRPs were detected. 2 patients developed MRP-associated infections. Both were discharged without long term health risks. Low gestational age and need for mechanical ventilation were risk factors for colonization with MRPs in the univariat analysis. The incidence density (per 1 000 patient days) for all MRE increased from 0.76 in 2011 to 3.51 in 2012. In contrast the sepsis rate remained stable (14.9% and 14.2%). 2 MRP colonization clusters were detected by routine microbiology swabs. Both could be controlled by appropriate hygienic measures.

CONCLUSIONS

The prevalence of Gram-negative MRPs increased in neonates. Microbiological screening seems to be helpful for early detection of colonization and thus prevention of nosocomial infections with MRPs. Despite the increased attention towards the problems associated with multiresistant bacteria, there are still major efforts needed for prevention and early treatment of sepsis with non-resistant bacteria.

A randomized double-blind crossover study of indoor air filtration and acute changes in cardiorespiratory health in a First Nations community

Few studies have examined indoor air quality in First Nations communities and its impact on cardiorespiratory health. To address this need, we conducted a crossover study on a First Nations reserve in Manitoba, Canada, including 37 residents in 20 homes. Each home received an electrostatic air filter and a placebo filter for 1 week in random order, and lung function, blood pressure, and endothelial function measures were collected at the beginning and end of each week. Indoor air pollutants were monitored throughout the study period. Indoor PM2.5 decreased substantially during air filter weeks relative to placebo (mean difference: 37 μg/m(3) , 95% CI: 10, 64) but remained approximately five times greater than outdoor concentrations owing to a high prevalence of indoor smoking. On average, air filter use was associated with a 217-ml (95% CI: 23, 410) increase in forced expiratory volume in 1 s, a 7.9-mm Hg (95% CI: -17, 0.82) decrease in systolic blood pressure, and a 4.5-mm Hg (95% CI: -11, 2.4) decrease in diastolic blood pressure. Consistent inverse associations were also observed between indoor PM2.5 and lung function. In general, our findings suggest that reducing indoor PM2.5 may contribute to improved lung function in First Nations communities.

PRACTICAL IMPLICATIONS

Indoor air quality is known to contribute to adverse cardiorespiratory health, but few studies have examined indoor air quality in First Nations communities. Our findings suggest that indoor PM2.5 may contribute to reduced lung function and that portable air filters may help to alleviate these effects by effectively reducing indoor levels of particulate matter.