Roofing as a source of nonpoint water pollution

Quality and seasonal variation of rainwater harvested from concrete, asphalt, ceramic tile and green roofs in Chongqing, China

“…The main factors affecting roof runoff quality include the following three aspects: 1) roof characteristics (e.g., type, age, roughness). The compounds contained in roofing materials can leach into the runoff (Chang et al, 2004) and older roofs contain large amounts of suspended solids; 2) rainfall characteristics (e.g., precipitation, rainfall intensity, ADWP); 3) Environment characteristics (e.g., seasonal variation, atmospheric pollution, roof surrounding environment). In general, roof temperatures are much higher than temperatures of other surfaces due to lower albedo and reduced shading effects from surrounding trees, which increases the rates of chemical reactions and organic decomposition of materials that have accumulated on rooftops (Chang and Crowley, 1993).…”

“…In general, roof temperatures are much higher than temperatures of other surfaces due to lower albedo and reduced shading effects from surrounding trees, which increases the rates of chemical reactions and organic decomposition of materials that have accumulated on rooftops (Chang and Crowley, 1993). In addition, the leaves, dead insects, and bird waste, added to roofs by interception and deposition affect the water quality of the roof runoff (Chang et al, 2004). Table 1 The seasonal variations of water quality from the concrete, asphalt and ceramic tile roofs.…”

“…Chang et al (2004) compared harvested rainwater quality from four roof types (wood shingle, composition shingle, painted aluminum, and galvanized iron) at Nacogdoches, Texas. They found that the pH, electrical conductivity (EC), and zinc levels were significantly influenced by the type of roofing material, and the runoff quality from wood shingles was the worst of the four roof types studied.…”

Assessment of Trace Metals Leaching During Rainfall Events from Building Rooftops with Different Types of Coverage – Case Study

“…routes of car communication, pavements and roofs of the buildings [Chang et al, 2004]. They cover approximately 80% of the total area [Kaye et al, 2006].…”

“…The analysis of runoff from roofs, in addition to providing information on the condition of the atmospheric air, also allows for the analysis of contaminants leached from the materials constituting the roof covering. The runoff from roofs may constitute an undesirable source of point pollution [Chang et al, 2004] with a composition depending on the composition of rainwater, roof age [Wallinder et al, 2001], type of coverage, inclination, location and meteorological factors [Evans et al, 2006]. The analysis carried out by Tsakovski et al [2010] showed the content of zinc within runoff from the roof covered with galvanized sheet was on an average level of 0.066 mg•dm -3 , while in the case of the roof covered with ceramic tiles, it ranged from 0.038 to 0.112 mg•dm -3 .…”