Pollutant concentrations can remain in the air for long periods after some activities. Further research is needed to better understand which health effects occur after exposure to the average pollutant concentrations found in homes and which occurs from the higher concentrations that occur for short periods of time. While pollutants commonly found in indoor air can cause many harmful effects, there is considerable uncertainty about what concentrations or periods of exposure are necessary to produce specific health problems. Other health effects may show up either years after exposure has occurred or only after long or repeated periods of exposure. On the other hand, rip currents are caused by the shape of the shoreline itself, and they may be sudden and unexpected. Air movement associated with infiltration and natural ventilation is caused by air temperature differences between indoors and outdoors and by wind. This includes some conditions found indoors, as well as conditions caused by outdoor impacts (such as climate change). The likelihood of immediate reactions to indoor air pollutants depends on several factors including age and preexisting medical conditions. In some cases, whether a person reacts to a pollutant depends on individual sensitivity, which varies tremendously from person to person.

The relative importance of any single source depends on how much of a given pollutant it emits and how hazardous those emissions are. Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the area. High temperature and humidity levels can also increase concentrations of some pollutants. Some effects may be made worse by an inadequate supply of outdoor air coming indoors or from the heating, cooling or humidity conditions prevalent indoors. Soon after exposure to some indoor air pollutants, symptoms of some diseases such as asthma may show up, be aggravated or worsened. Some health effects may show up shortly after a single exposure or repeated exposures to a pollutant. AQI is 151 – 200. Everyone may begin to experience some adverse health effects, and members of the sensitive groups may experience more serious effects. At first, people begin holding things farther away in order to see them in focus.

Though small, they’re capable of catching tiny prey and begin growing rapidly as they mature into adults. AQI is 101 – 150. Although general public is not likely to be affected at this AQI range, people with lung disease, older adults and children are at a greater risk from exposure to ozone, whereas persons with heart and lung disease, older adults and children are at greater risk from the presence of particles in the air. Some people can become sensitized to biological or chemical pollutants after repeated or high level exposures. Tactical Level Command and Control is where individual battles and engagements are fought. An AQI value of 100 generally corresponds to the national air quality standard for the pollutant, which is the level EPA has set to protect public health. AQI is 51 – 100. Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people. Finally, there are a number of mechanical ventilation devices, from outdoor-vented fans that intermittently remove air from a single room, such as bathrooms and kitchen, to air handling systems that use fans and duct work to continuously remove indoor air and distribute filtered and conditioned outdoor air to strategic points throughout the house.

Outdoor air can enter and leave a building by: infiltration, natural ventilation, and mechanical ventilation. Indoor Air Quality (IAQ) refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants. Some sources, such as building materials, furnishings and products like air fresheners, can release pollutants more or less continuously. Other sources, related to activities like smoking, cleaning, redecorating or doing hobbies release pollutants intermittently. Never-ending colds and flus: If it always seems like your cold or flu is lasting longer than anyone else’s, it may not actually be the flu – it could instead be a reaction to something in your air quality. AQI is 0 – 50. Air quality is considered satisfactory, and air pollution poses little or no risk. If too little outdoor air enters indoors, pollutants can accumulate to levels that can pose health and comfort problems.