Scientists explore how inequalities in air pollution exposure fluctuate

Researchers have begun to document how inequalities in exposure to air pollution fluctuate from day to day across 11 major US cities, finding that climate change could exacerbate these differences.

Studies have shown that air pollution disproportionately affects communities were economically disadvantaged people and Hispanic, Black and Asian people live.

As technology has improved, scientists have begun documenting these disparities in detail, but information on daily variations has been lacking.

Researchers have used satellite and other observations to determine how air quality varies on a small geographic scale, at the neighbourhood-level.

But this approach overlooks another crucial variable. ‘When we regulate air pollution, we don’t think of it as remaining constant over time, we think of it as dynamic,’ explained Sally Pusede, PhD., the project’s principal investigator.

‘Our new work takes a step forward by looking at how these levels vary from day to day,’ she said.

Information about these fluctuations can help pinpoint sources of pollution. For instance, in research reported last year, Pusede and colleagues at the University of Virginia found that disparities in air quality across major U.S. cities decreased on weekends.

Their analysis tied this drop to the reduction of deliveries by diesel-fueled trucks. On weekends, more than half of such trucks are parked. 

The scientists have analysed satellite-based data for 11 major UK cities, including Chicago, Atlanta, Los Angeles and Washington DC.

A preliminary analysis found the highest average disparity in Los Angeles for Black, Hispanic and Asian communities in the lowest socioeconomic status tracts.

They experienced an average of 38% higher levels of pollution than their non-Hispanic, white, higher socioeconomic status counterparts in the same city.

Washington, DC had the lowest disparity, with an average of 10% higher levels in Black, Hispanic and Asian communities in low-income tracts.          

Pusede’s research focuses on the gas NO2, which is a component of the complex brew of potentially harmful compounds produced by combustion.

Exposure to high concentrations of this gas can irritate the airways and aggravate pulmonary conditions. Inhaling elevated levels of NO2 over the long term can also contribute to the development of asthma.  

Pusede hopes to see this type of analysis used to support communities fighting to improve air quality. ‘Because we can get daily data on pollutant levels, it’s possible to evaluate the success of interventions, such as rerouting diesel trucks or adding emissions controls on industrial facilities, to reduce them,’ she says.

Photo by Oxxaca