Environmental Hospitalization Data

Find data on environmental hospitalization in Massachusetts, including information on asthma, acute myocardial Infarctions (heart attacks), carbon monoxide (CO) poisoning, chronic obstructive pulmonary disorder (COPD), and heat stress.

About the Data

The environmental hospitalizations dataset includes information on asthma, acute myocardial Infarctions (heart attacks), carbon monoxide (CO) poisoning, chronic obstructive pulmonary disorder (COPD), and heat stress. Environmental hospitalizations data are presented as two measures on this site: Hospital Admissions and Emergency Department (ED) visits. The hospital admissions measure includes patients who are admitted to the hospital and treated as inpatients. The ED visits measure includes patients who are treated and released in the ED, who are admitted as inpatients through the ED, and outpatient observation stays.

Image that shows the various forms of oppression that impact the various types of social determinants of health, that then impact health outcomes.


As you look at data on this webpage, you may see differences among population groups. The differences are especially noticeable between white people and people of color.

These differences exist because of structural racism. These differences are NOT because of an individual’s choices, behaviors, or identity.

Systems of oppression, such as racism, cause harm to everyone. They also influence the social determinants of health (SDoH), which impact health outcomes. See Figure 1.

It is important to keep these notes in mind when looking at the data and using it to inform public health efforts.

If you decide to share these data, remember to use racial equity context and framing. The DPH Racial Equity Data Road Map is one resource that can help.

About Environmental Hospitalizations

Environmental hospitalizations data can be used to monitor trends over time, help identify high-risk groups and assist with prevention, evaluation, and program planning efforts. In addition, these data can be linked to environmental data to provide a more in-depth examination of linkages between environmental and health data.

Hospitalization data are collected by the Massachusetts Center for Health Information and Analysis (CHIA) from all 74 Massachusetts acute care hospitals and satellite emergency facilities. DPH obtains information on Massachusetts residents who are discharged as inpatients (more than 23 hour hospital stay), outpatients (less than 24 hours hospital stay), and through emergency department (ED) visits data collected annually from CHIA. Hospitalization data includes information on patient characteristics and the medical treatment they received.

Hospitalization data, by definition, exclude discharges from specialty hospitals (e.g., psychiatric), long-term care facilities, and federal hospitals that are exempt from state reporting requirements.  Hospitalization data do not include individuals who do not receive medical care or who are not hospitalized.  Rates are based on the residential location of cases and not necessarily the location where incidents occur. When comparing rates across geographic areas, factors such as access to medical care and health behaviors (e.g., diet or exercise) must also be considered.

Since some patients enter the ED and are later admitted to the hospital as inpatients, these patients are included in both the ED visit and hospital admission dataset. For this reason, there is overlap between the two measures. Consequently, counts and rates should not be summed across the two measures of hospitalization.

Data will only be presented to the public if the confidentiality rules of MDPH and CHIA are met. These are rules requiring data aggregation and cell suppression to protect privacy.

Asthma hospitalizations

Asthma is a chronic lung disease that causes the airways that carry air into and out of the lungs to become irritated and swollen, which causes less air to flow into the lungs. In Massachusetts, children younger than five years of age have had the highest rates of emergency department visits, outpatient observation stays, and hospitalization due to asthma. Adults age 65 years and older have the second highest rate of hospitalization due to asthma.

A number of studies have reported links between being exposed to air pollution and asthma. Asthma hospitalization measures can be used to evaluate the impact of ambient air pollution on respiratory health and can be used for better resource management to further reduce asthma-related expenditures and monitor spatial and temporal trends for asthma.

Age-adjusted rates for asthma hospitalization admissions and ED visits for all ages are available on this site.

Heart attack hospitalizations

An acute myocardial infarction, also known as a heart attack, occurs when the blood supply to the heart is severely reduced or completely blocked.  In Massachusetts, heart disease, stroke, and other diseases of the heart and blood vessels are responsible for approximately 35% of all deaths in the state. Risk factors for heart attack include health, lifestyle, and environmental factors. Environmental factors include exposure to certain air pollutants, such as particulate matter, which can increase the rate of heart attack, arrhythmias, and premature death.

Tracking heart attack hospitalizations allows for monitoring trends over time and identifying high-risk groups. These data can be used to examine time trends in heart attack hospitalizations, identify seasonal trends, and identify possible environmental relationships warranting further investigation or environmental public health action when heart attacks are linked with environmental variables.

Because nearly all heart attack hospitalizations result in an inpatient admission, data are not presented for heart attack ED visits. On this site, only age-adjusted rates for heart attack hospitalization admissions are available.  Heart attack rates are based on the age groups most affected by this disease so rates are only calculated among people 35 years of age and older.

CO poisoning hospitalization

Carbon monoxide (CO) poisoning results from breathing air that contains CO gas that can cause a range of symptoms from mild to severe, including death. CO is a tasteless, odorless and colorless gas that can come from a variety of sources.  It is produced by the incomplete burning of various fuels including, gasoline, coal, wood, charcoal, oil, kerosene, propane, and natural gas.

Every year over 400 deaths in the United States are estimated to occur as a result of accidental, non-fire related exposure to this toxic gas. The release of CO is almost entirely preventable by the correct installation, maintenance, and operation of devices that may emit carbon monoxide. Tracking the occurrence of CO poisoning hospitalization can support public health prevention and intervention activities. It can also provide information on unrecognized exposures such as spikes in CO poisoning after disasters and storms due to emergency generator use.

Age-adjusted rates for CO poisoning hospitalization admissions and ED visits for all ages are available on this site. There is no information about specific sources of CO poisoning, but hospitalizations are identified as being fire-related, non-fire related, or unknown.

COPD hospitalizations

Chronic Obstructive Pulmonary Disease, or COPD, refers to a group of diseases including emphysema and chronic bronchitis that block airflow and cause breathing-related problems.  COPD is often preventable and treatable. In Massachusetts, COPD is consistently among the top ten reasons for hospital admission.

Although the primary cause of COPD is smoking, a number of studies have reported associations between indoor and outdoor air pollution exposures and COPD.  COPD hospitalization measures can be used to evaluate the impact of indoor and outdoor air pollution on respiratory health and monitor spatial and temporal trends for COPD.

Age-adjusted rates for COPD hospitalization admissions and ED visits are available on this site. COPD rates are based on the age groups most affected by this disease so rates are only calculated among people 25 years of age and older.

Heat stress, also known as heat-related illness, is a preventable illness that occurs when heat exposure exceeds the body’s capacity to cool itself. When this happens, the core body temperature will rise and a range of heat-related symptoms and conditions may develop. Any individual, regardless of age, sex, or health status can develop heat stress. The very young, the elderly and those with chronic health conditions such as cardiovascular disease, diabetes, or obesity, are more susceptible to the effects of heat.

Hospitalization rates for heat stress are just one potential indicator of the impact of climate change. In 2010, the Massachusetts Department of Public Health received funds from CDC to evaluate the state’s vulnerabilities and readiness to address climate change-related health impacts. Tracking heat stress hospitalizations using a standardized method allows for the monitoring of trends over time and the identification of high-risk groups that may be more susceptible to heat stress incidents.

Nearly all heat stress hospitalizations begin with an ED visit.  After being examined and/or treated in the ED, some patients are then discharged while others require further monitoring or treatment and are admitted to the hospital as inpatients.  Age-adjusted rates for heat stress hospitalization admissions and ED visits for all ages are available on this site.

Continue Exploring PHIT Data

Additional Resources

Contact   for Environmental Hospitalization Data


Population Health Information Tool Information Email Population Health Information Tool (PHIT) at DPH.PHIT@mass.gov


250 Washington Street, Boston, MA 02108

As a publicly available tool, we highly encourage the use of data included in PHIT. Below is an example of how you can cite this webpage to reference any information you find helpful.

[Insert Title of Webpage Here] (n.d.). Population Health Information Tool, Massachusetts Department of Public Health. [Insert URL]

Help Us Improve Mass.gov  with your feedback

Please do not include personal or contact information.