The Baltimore region in a manner similar to other metropolitan areas throughout the nation experienced a rapid and substantial loss of agricultural and extractive/barren land during the past three decades. Data compiled by the Maryland Department of Planning and presented in its land use and land cover data for 1973-2002 shows that the amount of land consumed for development rose by almost 179 thousand acres with roughly 112 thousand acres being used exclusively for low density residential development. The explosion of low density growth accounted for 62 percent of land development occurring in the region between 1973 and 2002.

Medium and high density growth consumed another 44 thousand acres during the 1973-2002 period so that residential growth accounted for 156 thousand acres of development or 87 percent of all new development in the region. While commercial, industrial, and institutional land consumption did grow, its growth paled before the amount of land set aside for residential development. As a result of this pronounced residential growth, our region lost 176 thousand acres of agriculture and forest lands between 1973 and 2002. The rapid pace of primarily residential development has caused the "built-up" portion of our region to rise from roughly one quarter (23.2%) of our region’s land area in 1973 to greater than one-third (35.7%) of our land area in 2002.

The Baltimore region recorded significant improvements in most key measures of air quality in the 1990’s and the trend continues for the early 2000’s. Levels of lead, nitrogen, dioxide, sulfur dioxide, inhalable particulates (PM10) and carbon monoxide are well below national air quality standards.

Recently, the Environmental Protection Agency has revised the federal standard for ground-level ozone to be an 8-hour standard. The one-hour ozone standard was revoked in June 2005. The Baltimore region was designated nonattainment for this new 8-hour ozone standard. In addition, the EPA has added a federal standard for fine particulate matter (PM2.5). The Baltimore region is no currently reaching the PM2.5 standard.