Diesel particulate matter (PM) consists of very small particles that are formed from diesel burning engines. This indicator measures the average daily amount of particulate pollution from diesel sources for the month of July.

Everyone should be able to live in neighborhoods where it is safe to breathe. Since diesel particulate matter is so small, it can reach deep into people’s lungs. This can increase the risk of cardiovascular disease and mortality. It can also cause adverse respiratory outcomes such as chronic obstructive lung disease, asthma, altered pulmonary function, and other symptoms. In California, the Air Resources Board estimates that approximately 3,500 deaths each year can be attributed to diesel PM exposure.¹¹⁹ Diesel PM is especially dangerous for children, exacerbating pulmonary inflammation and other risks. Evidence that links diesel PM to low birth weight and infant mortality is growing.¹¹⁹

To address high levels of diesel particulate matter, jurisdictions should prioritize strategies to reduce emission levels, while also helping to protect residents from current pollution.

While diesel engines are used in a variety of applications, they are especially concentrated in freight such as ports, trucking, and railways. Throughout California, low-income communities and communities are disproportionately exposed to the emissions from freight facilities. Local jurisdictions working to address the health impacts of diesel pollution should carefully assess the distribution of freight pollution by race, income, immigration status, neighborhood and other factors, and take strong and proactive steps to counter inequities.

While local jurisdictions do not have regulatory authority over most stationary sources and tail pipe (mobile source) emissions, there are many actions local jurisdictions can take to reduce pollution. They can incentivize or require Low-Emission Vehicles and Freight Facilities in many situations. They can also work with their local Air Quality Management District to Reduce Emissions from Other Sources, like construction, homes, and other stationary sources.

In addition to reducing pollution, it is essential to find ways to protect residents from existing diesel particulate matter sources and other emissions. Jurisdictions can Separate People from Pollution sources by using planning tools to ensure that new residential development and schools are not adjacent to these sources, and to encourage ending existing incompatible land uses. Where pollution and people must co-exist, jurisdictions can Reduce Exposure to Pollution by encouraging healthy design standards and accurate information collection and response to existing risks. Finally, jurisdictions can Build Community Power and Connection and partner with communities to address air quality issues.

For all strategies, jurisdictions should direct and prioritize efforts for places already overburdened by air pollution, and work to address existing inequities in health. In addition to relieving existing burdens, jurisdictions should identify opportunities to maximize additional health or quality of life benefits that can be achieved in addition to decreased pollution. For instance, Weatherization Programs can improve indoor air quality, reduce asthma triggers, provide job training opportunities, and save residents money. Local governments should prioritize interventions that minimize risk in vulnerable communities, while maximizing benefits that meet community needs.