Indoor Environment
BREATHE Center studies have shown that children living in Baltimore City often live in homes where the indoor air quality is worse than outdoor air quality.
In a study of preschool children's homes, the average fine particle pollution in the air was 40 micrograms per cubic meter of air (µg/m3) while average outdoors was 10 µg/m3.2 That’s four times the amount of particulate matter inside versus outside.
But what is fine particulate air pollution, known as PM2.5, and why should you care?
PM2.5 Size
Fine particle air pollution, known as PM2.5, can travel deep into the respiratory tract, reaching the lungs and entering the blood stream.
PM2.5 and Risk
If the level of PM2.5 is above 5 μg/m3, the air is considered unhealthy for people with existing breathing issues such as asthma.3 Typical indoor weekly averaged PM2.5 levels in Baltimore homes ranges from 10-40 μg/m3, but can be as high as 300 μg/m3.
Common PM2.5 Sources
Outdoors, PM2.5 is produced by vehicle exhaust and fuel burning. Indoors, PM2.5 is produced by smoking, cooking, and using fireplaces.
Smoking indoors not only affects the person smoking, but others who are in the space. Indoor PM2.5 exposure is associated with poorer respiratory and cardiovascular outcomes.
Baltimore’s smoking rate has been consistently above state and national averages since 2002. Although all rates were decreasing at a similar pace initially, since 2008 Baltimore’s rate has been declining less rapidly, widening the gap between the city and the rest of the state and the country. As of 2016, Baltimore City was still five years behind Maryland in terms of reducing smoking rates.
Baltimore residents who are 26+ years old are driving the difference in smoking rates between Maryland and Baltimore City. On the other hand, younger age groups seem to have smoking rates comparable to other locations.
How to read this map
When there is only one range of values, it is a choropleth map. Choropleth maps show the value of a variable in a geographical area such as community statistical area or census tract. In this case, the map shows that there are more adults who smoke in areas with darker brown and fewer people who smoke in areas with lighter brown.
The number of adults who smoke is not evenly distributed across the city. In the map on the left, the darker the area, the more adults living there smoke. These differences occur because smoking habits are shaped by different social circumstances.
Drag the slider to compare adult smoking rates to the change in smoking rates between 2002 and 2016. The darker red areas mean there was a significant increase in smoking prevalence. The dark green areas mean there was a decrease.
Gas stoves are another source of indoor particulate matter. Cooking on a gas stove three or more times a day without proper ventilation increases PM2.5 to unhealthy levels, especially for those already experiencing breathing issues such as asthma.
How to read this map
When there are two values and multiple shades, it’s a bivariate choropleth map. Bivariate choropleths show the values of two variables at once so their relationship can be understood. Bivariate choropleths visualize where two variables tend to be in agreement or disagreement geographically.
This example shows the relationship between gas and electric heating. Both variables have high values in the brown areas, gas alone is high in the yellow areas, and electric alone is high in purple areas.
Gas is the most commonly used resource to heat homes in Baltimore City and it is also responsible for increases in PM2.5 and other pollutants inside and around homes.
Most of the homes in Baltimore City are being heated by gas. Only a few areas, mostly in the downtown area, are predominantly using electricity
In terms of gas use, Baltimore City is above US, Baltimore Metropolitan Area, and Maryland with more than 60% of homes using gas versus 35-45% in other geographies.
Another indoor exposure of concern is allergens from animals, especially pests like mice and cockroaches. Exposure to an allergen found in mouse urine that is circulating in the air increases the risk for developing allergic sensitivity. For children who have allergic asthma, exposure to these allergens can worsen their asthma, doubling the risk of needing to go to the emergency room.4