As part of an immune response to foreign pathogens, histamine is produced by basophils and by mast cells found in nearby connective tissues. Histamine increases the permeability of the capillaries to white blood cells and some proteins, to allow them to engage pathogens in the infected tissues.
Where vegetation is sparse, temperature is hot. (Image: NASA) An urban heat island (UHI) is a metropolitan area which is significantly warmer than its surroundings. According to the EPA, many U.S. cities have air temperatures up to 10Â°F (5.6Â°C) warmer than the surrounding natural land cover.
Unlike the vast majority of the state, New York City features a humid subtropical climate (Koppen Cfa). New York City is an urban heat island, with temperatures 5-7 degrees Fahrenheit (3-4 degrees Celsius) warmer overnight than surrounding areas. In an effort to fight this warming, roofs of buildings are being painted white across the city in an effort to increase the reflection of solar energy, or albedo.