The Ambient Air Monitoring Program measures ground-level concentrations of criteria pollutants and air toxics, along with surface and aloft meteorological parameters. The Program also performs quality control, quality assurance, and analysis of the pollutant concentrations that are measured at each of the air monitoring stations located throughout Maryland. It is responsible for Air Quality Index (AQI) reporting and issuing daily air quality forecasts as well as coordination of 3D air-shed photochemical grid and dispersion modeling.
In addition, the Program collaborates with local universities to conduct special atmospheric monitoring research to better characterize aloft and surface atmospheric pollutant concentrations. These research initiatives support air quality planning and regulations development.
While generally Good air quality is expected to continue, some diffuse wildfire smoke will impact the region beginning Tuesday night, lingering through Thursday morning. The smoke may at times be perceptible, but daily average fine particle concentrations will remain within the Good range the next three days. A diffuse, though widespread plume of wildfire smoke aloft is overhead Tuesday evening and, through subsidence and vertical mixing, will mix into the surface layer Wednesday. This will bring some fine particulate pollution associated with the smoke to the surface on Wednesday, but concentrations are currently expected to remain in the Good range for the daily average. Winds are light on Thursday. Some slightly elevated concentrations of fine particles may persist due to the smoke, but Good air quality should prevail. Any lingering wildfire smoke will leave the area through the day Thursday and depart by Friday. Good air quality persists Friday as a result of clouds and the smoke’s departure. –MDE
Pollen can exacerbate the effects of pollution and vice versa. Get the latest pollen counts and forecast here: Pollen.com
To report an environmental emergency, see Emergency Numbers.
Last fall, the U.S. Environmental Protection Agency strengthened the health-based air quality standard for ozone, lowering the standard from 75 parts per billion (ppb) to 70 ppb. The updated standard will improve public health protection, particularly for at-risk groups such as children, older adults, people with heart or lung diseases and outdoor workers. Because of the new, more stringent yardstick being applied to ozone levels, the number of poor air days that are forecast and observed is expected to increase by about 30 percent. This doesn’t mean air quality has suddenly gotten worse. It means a more protective standard is now in place.
Have you heard the term “inversion” but not really understood what it means? An inversion is simply when temperature increases with increasing height. Normally temperature decreases with increasing height. This decrease in temperature is what allows snow on mountain tops while it may be sweltering at the mountain base. Inversions themselves are invisible – we can’t see the air. However, we can see what affect inversions have on the atmosphere. That’s becauseinversions act as a lid and trap whatever is emitted between them and the ground. This is particularly evident with pollution and most apparent during the winter months when inversions are typically the strongest. In the animated image to the left, a strong morning inversion developed over Maryland on Wednesday, January 6, 2016. Downtown Baltimore can be seen in the center left of the image. The image spans from 9am to 5pm local time. Without sunlight, inversions strengthen. As the sun had only risen briefly by 9am, the inversion on January 6th was near its lowest height (strongest intensity) of the day as often occurs near sunrise. Trapped pollution is evident as a “brownish” color due to elevated concentrations of nitrogen dioxide very near to the ground which is emitted from cars and other combustion sources. At the beginning of the animation, the brown area is very near the ground (lower black line) while up above a very blue, clean sky is visible, evidence of clean air. Over the course of the next few hours, the inversion “lifts”, that is, the pollution of the city (the brownish area) rises to a higher height (upper black line noted on the image). This increase in height of the inversion decreases pollution concentrations near the surface and is why in winter time, the most polluted part of the day is often in the early morning hours. *The white plume seen in the center of the image is steam. It illustrates changing wind direction during the day due to heating differences between the water and land.
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