An indoor air quality system for a building, comprising: an IAQ sensor that is located within the building and that is configured to measure an IAQ parameter, the IAQ parameter being one of: a relative humidity of air; an amount of particulate of at least a predetermined size present in air; an amount of volatile organic compounds (VOCs) present in air; and an amount of carbon dioxide present in air; characterized in that the system comprises: a mitigation module configured to: selectively turn on a mitigation device based on a comparison of the IAQ parameter with a first threshold; and selectively turn off the mitigation device based on a comparison of the IAQ parameter with a second threshold; and a thresholds module configured to set the first and second thresholds to predetermined default values; wherein the mitigation module is configured to maintain the mitigation device off throughout a predetermined period; wherein the IAQ system further comprises a baseline module configured to determine a baseline value of the IAQ parameter for the predetermined period based on values of the IAQ parameter measured during the predetermined period; wherein the thresholds module is configured to selectively adjust at least one of the first and second thresholds based on the baseline value of the IAQ parameter, the selective adjustment including at least one of increasing and decreasing. an IAQ sensor that is located within the building and that is configured to measure an IAQ parameter, the IAQ parameter being one of: a relative humidity of air; an amount of particulate of at least a predetermined size present in air; an amount of volatile organic compounds (VOCs) present in air; and an amount of carbon dioxide present in air; a relative humidity of air; an amount of particulate of at least a predetermined size present in air; an amount of volatile organic compounds (VOCs) present in air; and an amount of carbon dioxide present in air; characterized in that the system comprises: a mitigation module configured to: selectively turn on a mitigation device based on a comparison of the IAQ parameter with a first threshold; and selectively turn off the mitigation device based on a comparison of the IAQ parameter with a second threshold; and a thresholds module configured to set the first and second thresholds to predetermined default values; wherein the mitigation module is configured to maintain the mitigation device off throughout a predetermined period; wherein the IAQ system further comprises a baseline module configured to determine a baseline value of the IAQ parameter for the predetermined period based on values of the IAQ parameter measured during the predetermined period; wherein the thresholds module is configured to selectively adjust at least one of the first and second thresholds based on the baseline value of the IAQ parameter, the selective adjustment including at least one of increasing and decreasing. a mitigation module configured to: selectively turn on a mitigation device based on a comparison of the IAQ parameter with a first threshold; and selectively turn off the mitigation device based on a comparison of the IAQ parameter with a second threshold; and selectively turn on a mitigation device based on a comparison of the IAQ parameter with a first threshold; and selectively turn off the mitigation device based on a comparison of the IAQ parameter with a second threshold; and a thresholds module configured to set the first and second thresholds to predetermined default values; wherein the mitigation module is configured to maintain the mitigation device off throughout a predetermined period; wherein the IAQ system further comprises a baseline module configured to determine a baseline value of the IAQ parameter for the predetermined period based on values of the IAQ parameter measured during the predetermined period; wherein the thresholds module is configured to selectively adjust at least one of the first and second thresholds based on the baseline value of the IAQ parameter, the selective adjustment including at least one of increasing and decreasing.